A fossil pterosaur|
Pterosaurs were flying creatures formerly known as pterodactyls and once believed to be reptiles. First known from the late Triassic, 220 million years ago, they were the earliest vertebrates to fly. They took to the air earlier then even the earliest bird. The smallest were the size of a sparrow, the largest, the size of a small airplane, with a wingspan of nearly forty feet.
They lived in the Mesozoic, the so-called Age of Reptiles, so they have long been considered reptiles. But ideas on this point are now changing. These animals are known only from fossils, and the hard parts of the body are usually the only portions of an animal that fossilize — in the case of a pterosaur this means bones and teeth. However, a few well-preserved fossils of pterosaurs clearly show the presence of hair, which indicates that these animals were bat-like warm-blooded mammmals, and not reptiles at all.